Intermittant A/C

“drop in power from the pedestal but I have no way of checking that.”

Time to consider an autoformer, and yes you can check voltage easily and inexpensively. $14

See https://www.rvupgradestore.com/Hughes-Autoformer-AC-Volt-Meter-p/dvm1221.htm

rockcandymountain wrote:
My Dutchman Denali 5th Wheel has a Dometic Roof Air Unit

Almost all of the time, it runs just fine.

Every once in a while, it will shut off and restart at what sounds like a slower fan speed. Then after a minute or two it will shut off again and restart at normal fan speed. Its almost like the rig is getting a drop in power from the pedestal but I have no way of checking that.

That's not good. It will eventually burn up your unit. Unplug the converter. This will allow the AC the full incoming power (your converter cycles as needed).

jdc1 wrote:

rockcandymountain wrote:
My Dutchman Denali 5th Wheel has a Dometic Roof Air Unit

Almost all of the time, it runs just fine.

Every once in a while, it will shut off and restart at what sounds like a slower fan speed. Then after a minute or two it will shut off again and restart at normal fan speed. Its almost like the rig is getting a drop in power from the pedestal but I have no way of checking that.

That's not good. It will eventually burn up your unit. Unplug the converter. This will allow the AC the full incoming power (your converter cycles as needed).

Explain your reasoning behind this statement. The converter only pulls at max about 3 amps. If you unplug your converter, then your RV will go dead from the battery going dead after a few days. The Converter has NO BEARING on RV roof AC operation. Doug

THat does sound like a low voltage coupled with a hard start so the motor tries (But fails) to start. overheats. shuts down and gets lucky on the 2nd try.

Two things to check/watch and a suggestion

THe voltage if it's a 50 amp rig you need to identify an outlet on the same leg as the A/C 30 amp rigs all same leg.

When MY Rig was new sometimes one A/C would work, Sometimes the other. sometimes both or neither.. Well my first stop at the tribble hunt was the power distribution center (Breaker box).. where I noticed one of the supposedly tightly clamped in the breaker wires moved about rather easily.. (WOW) So I first formed a theory "Many RVers have a few screws loose" (Actually that came later) and then broke out the #2 Square bit and counted turns to find out HOW loose one took 3 1/2 turns before I was happy with it. (The theory came after chatting with other RVers who told me this is common) (I know other folks who think we have a few screws loose too but I don't think a #2 bit will help them :)

Check all the wires in the box. Black, White or bare/green Pull the shore pulg first and use a flashlight.

If your A/C fan is in the automatic fan setting, the units fan will stop and shift speeds trying to adapt to the thermostats setting when ambient temp and setting temp are 3-4 degrees apart.. Try putting the fan in low or high speed when temperature differential is several degrees apart.

Buy a kill-a-watt meter. Monitor voltage. Correct low voltage with an autoformer.

Each time the roof air goes through the event you describe, there is cumulative permanent damage.

dougrainer wrote:

jdc1 wrote:

rockcandymountain wrote:
My Dutchman Denali 5th Wheel has a Dometic Roof Air Unit

Almost all of the time, it runs just fine.

Every once in a while, it will shut off and restart at what sounds like a slower fan speed. Then after a minute or two it will shut off again and restart at normal fan speed. Its almost like the rig is getting a drop in power from the pedestal but I have no way of checking that.

That's not good. It will eventually burn up your unit. Unplug the converter. This will allow the AC the full incoming power (your converter cycles as needed).

Explain your reasoning behind this statement. The converter only pulls at max about 3 amps. If you unplug your converter, then your RV will go dead from the battery going dead after a few days. The Converter has NO BEARING on RV roof AC operation. Doug

Three amps is three amps. If the guy has no means of checking the amperage, then this MIGHT help to see if it is a low amperage connection at the pedestal. Having that 3 amps of power just might put the power above what is needed for the AC. The fridge can run on propane while he checks this.

You might try not being so pushy to all the people you reply to.

Retired JSO wrote:
If your A/C fan is in the automatic fan setting, the units fan will stop and shift speeds trying to adapt to the thermostats setting when ambient temp and setting temp are 3-4 degrees apart.. Try putting the fan in low or high speed when temperature differential is several degrees apart.

If it is a electronic thermostat this is the answer. It is normal. The thermostat is trying to maximize efficiency.

rockcandymountain wrote:
It's almost like the rig is getting a drop in power from the pedestal but I have no way of checking that.

That's common in crowded parks in very hot weather when everyone is running a/c. Make sure your electric water heater isn't robbing power.

One thing to check which you can do without any equipment is to see if your pedestal plug is getting hot.

rockcandymountain wrote:
My Dutchman Denali 5th Wheel has a Dometic Roof Air Unit

Almost all of the time, it runs just fine.

Every once in a while, it will shut off and restart at what sounds like a slower fan speed. Then after a minute or two it will shut off again and restart at normal fan speed. Its almost like the rig is getting a drop in power from the pedestal but I have no way of checking that.

That is exactly what they do with the fan set to auto. Read the manual.

When mine starts to hunt the perfect speed like you described I change the fan to low speed. It's usually in the evening when the outside temperature is dropping, later on I change it back to auto fan.

Nothing is wrong - no worries.